<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
		.container{
		  width: 600px;
		  height: 400px;
		  display: grid;
		  grid-template-columns: 200px 1fr;
		  grid-auto-rows: 80px 1fr 1fr;
		  grid-gap: 10px;
		  grid-template-areas:
		    "toolbar toolbar"
		    "tree table"
		    "tree subtable";
		}
		.item {
		  background: skyblue;
		}
		.toolbar{
		  grid-area: toolbar;
		}
		.tree{
		  grid-area: tree;
		}
		</style>
	</head>
	<body>
		<div class="container">
		  <div class="item toolbar">toolbar</div>
		  <div class="item tree">tree</div>
		  <div class="item table">table</div>
		  <div class="item subtable">subtable</div>
		</div>
	</body>
</html>